Life vests are provided on ships and airplanes as a safety feature in case of an airplane crash into water or a ship's sinking. Such devices are normally adapted to be placed over the user's head and depend from his neck along his chest and abdomen. Such vests are usually provided with a gas supply in the form of a sealed gas cylinder which is adapted to provide sufficient gas to the vest quickly. The sufficient amount of gas is intended to be that which will provide enough buoyancy to the user to maintain his head out of the water. Generally, 23 lbs. of buoyancy is enough to compensate for the lack of sufficient natural buoyancy in the person to maintain his head out of the water. However, in heavy waves the user's momentum going between the peaks and troughs of the waves is often sufficient to momentarily submerge his head. As the height of the waves is increased, the chances of drowning are also increased as the length of time with the head under the water is increased. Moreover, merely submerging the head briefly can have the effect of disorienting the user and this may increase his chances of becoming separated from other crash or shipwreck survivors. These problems are greatly increased if the user is injured or unconscious.
Dual chambered life vests are often provided as an additional safety feature. If one chamber fails, some buoyancy will remain in the other chamber to assist in maintaining the user's head out of the water. Another safety feature often incorporated in life vests is an oral inflating tube. These tubes are provided in case of failure of the gas cartridge to supply sufficient gas to inflate the vest, and the air tube is also a source of air in case of a slow leak in the vest's chamber.
In order to provide more buoyancy in a life vest, the volume can be increased. However, the additional buoyancy yielded from a larger vest is often not needed. It is advantageous that the life vest be completely filled in order that the vest provide sufficient support about the neck. Obviously, if a larger volume vest were used and the amount of buoyancy were to be decreased, the pressure in the life vest would be decreased and this would result in the loss of support about the neck. Therefore, it would be advantageous to have a life vest which would be fully pressurized at two different buoyancies.
As mentioned above, it is advantageous to have a dual chambered life vest. However, because of the force exerted between chambers, it is difficult to bend the vest to conform it to the front of the user. Conforming the vest to the user's front is important to ensure the proper attitude of the user's body in the water. As many vests are provided with straps extending from the bottom of the vest and going around the user, if the bottom of the vest is closer to the user, the amount of strap needed with each vest is decreased and results in an overall savings in the cost of each life vest.
Many life vests are provided with small lights which are electrically connected to water actuated batteries. The lights are useful at night to indicate the user's location to potential rescuers and to fellow survivors. Many such batteries are mounted directly to the underside of the vest. In that location, the batteries constantly remain in the water. If the user activates the battery at night but there is still usable power in the battery at dawn, there is no way to conserve that energy.
As stated above, life vests have auxiliary oral tubes in order to provide a supplementary source of air. It is advantageous that the auxiliary tubes be kept out of the way during donning of the vest so as not to interfere with the head of the user. It is also important that the tubes be easily accessible both to the user and to another person who might have to inflate the vest if the user is unable to do so.
One relatively minor safety problem occurring with life vests concerns the situation when the user fills the vest with air using the oral tube and then accidentally actuates the gas cylinder. In that case, the vest could become overpressurized and burst.
Therefore, the main object of the present invention is to overcome the above mentioned difficulties occurring in prior life vests. Specifically, it is an object of the present invention to provide a life vest with two amounts of buoyancy, each level of buoyancy occurring when the life vest is rigid from full pressurization. In accomplishing this object, the other object of providing a safety release for subsequent gas cylinder actuation after prior oral inflation is also accomplished. Another object of the invention is to have a dual chambered life vest which conforms to the user's chest and abdomen while the vest is around his neck. Another object is to provide a battery mounting with which the battery can be removed from the water during daylight hours to prevent the total depletion of available power therein. Other objects will become evident in the remaining portion of the specification.